This is an improvement on the previously filed application Ser. No. 07/726,342 filed Jul. 3, 1991, now U.S. Pat. No. 5,201,461 invented by John M. Sykora.
As stated in the previous application, paperboard cartons are used in vast quantities for a multitude of shipping and storing purposes. There are typically two commercial ways of manufacturing paperboard cartons. The first way is to manufacture a single, flat paperboard blank which is made of a single, integral sheet of paperboard and which is scored and cut in a desire manner so that the desire container may be prepared by folding of the blank when that is desired. Typically, the containers are shipped in their flat, blank form to their point of use, where they are assembled by a simple process of folding along the score lines.
As a second commercial method for making paperboard cartons, the cartons may be made with a separate preformed bottom and top, and then the respective bottoms and tops are united by gluing together or the like. It is known in the prior art to use different paperboard grades or types in the manufacture of paperboard cartons by this prior art means, which does not make use of a single, flat blank to assemble a complete carton, but rather one preassembles two container sections, and then joins them together.
Paperboard cartons may comprise both sleeves, which typically carry inner boxes, and the boxes themselves.
The manufacture of cartons from a single, flat blank is particularly desirable in terms of efficiency and low cost. However, in the prior art there is often a need to be met or an advantage to be obtained if a certain portion of the container is of a different type of paperboard material from another portion. For example, it might be desirable for a portion of the container to be made of a less expensive, weaker material having a smaller wall thickness. Also, the situation may arise where a portion of the material of the container could be virgin, fresh paperboard, and another portion could be recycled paperboard, which will generally be of less strength, all things being equal.
Likewise, it may be desirable for a portion of the container to be made of an oiled or plastic impregnated paperboard so that it is water resistant, while it may be unnecessary for the entire container to be so oiled or plastic impregnated.
If it were possible for portions of the container to be free of oiling or plastic impregnation, or if it were possible for some of the container to be of recycled material, a cost saving could be accomplished in the container. However, such has not been done prior to the invention described in Sykora Ser. No. 07/726,342, while making use of the single, flat blank technique for manufacture of the carton. Rather, people have been separately manufacturing the bottom and top of a container, for example, made of different materials as desired, and then uniting them, which is a more expensive process.
By this invention, an economical container made of a single, flat blank is provided in which portions of the paperboard present are different from each other, for purposes of economy or for purposes of special functioning, as may be desired and with the improvement of this application the flat blank reinforced in its joining portion by mirror imaged minor walls that have tab portions that form a double panelled wall as well as double panelled corner tab portions upon assembly of a carton so that it has better load bearing characteristics needed in some instances for better stackability.